One who fights with fists, or someone who makes fists; a boxer or fighter.
From fist with the agent suffix -er, meaning 'one who performs the action of fisting.' This occupational noun emerged in English during the medieval period to describe combatants.
Before the word 'boxer' became common, 'fister' was an actual job description—bare-knuckle fighters would be hired for exhibitions and wagers throughout medieval Europe and early America!
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